Self-photoinitiated oligomers of water-diluted polyurethane acrylate grafted with zinc oxide of low concentrations Check for updates

In order to eliminate some problems of organic photoinitiators, self-photoinitiated oligomers of water-diluted polyurethane acrylate grafted with 0.1-0.3 wt.% zinc oxide (ZnO) were prepared. ZnO was first facilely treated by vacuum dehydration and sonication, and then reacted into the oligomers by -NCO and -OH groups. The oligomers were synthesized using toluene diisocyanate, polyether diols, 2, 2-dimethylol propionic acid, hydroxyl propyl acrylate, pentaerythritol triacrylate, ZnO, and triethylamine. The prepared oligomers were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, particle size analyzer, and UV-vis spectroscopy. The kinetics of the UV-curing process was investigated. We observed a maximum kinetic rate constant with ZnO content of 0.2%, and the best film performance with ZnO content around 0.25%. The photoinitiation efficiency of the oligomers was similar to the value of 2-hydroxyl-2-methyl-1-phenyl-1-propanone. In general, the physical properties of the films with physically mixed ZnO were worse than those of the films with chemically grafted ZnO. This investigation demonstrated novel oligomers grafted with a few ZnO can be self-photoinitiated and facilely prepared.